THIS IS A WARNING MESSAGE ONLY.

YOU DO NOT NEED TO RESEND YOUR MESSAGE.

Delivery to the following recipient has been delayed:

     neeku.sh@gmail.com

Message will be retried for 2 more day(s)

Technical details of temporary failure:
Google tried to deliver your message, but it was rejected by the server for the recipient domain gmail.com by gmail-smtp-in.l.google.com. [2607:f8b0:4001:c14::1b].

The error that the other server returned was:
450-4.2.1 The user you are trying to contact is receiving mail at a rate that
450-4.2.1 prevents additional messages from being delivered. Please resend your
450-4.2.1 message at a later time. If the user is able to receive mail at that
450-4.2.1 time, your message will be delivered. For more information, please
450-4.2.1 visit
450 4.2.1  https://support.google.com/mail/answer/6592 s64si14307930ioi.19 - gsmtp


----- Original message -----